The suggested mark is a careful word match, not a teacher’s mark. If you said the same science in different words, give yourself the mark.
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14 questions · 60 marks, in lesson order.
What are plastics?
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A raincoat is made from a plastic that is waterproof, lightweight and flexible. Answer the parts to explain why it is a good choice.
What does waterproof stop?
(1)So how does this help the person wearing it?
(1)Why is lightweight useful for a coat?
(1)Why is flexible useful for a coat?
(1)Total for this question: 4 marks
What are plastics?
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The table shows some properties of three plastics, A, B and C.
| plastic | flexible? | transparent? | temperature at which it softens / °C |
|---|---|---|---|
| A | no | yes | 80 |
| B | yes | yes | 75 |
| C | no | no | 160 |
Which plastic is best for a flexible, see-through food wrap?
(1)A kettle body must hold boiling water at 100 °C. Use the table to explain why plastic C is better than plastic A for a kettle body.
(2)Some plastics are made of long, tangled polymer chains. Explain how this structure allows the plastic to stretch.
(1)Total for this question: 4 marks
Making plastics
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A class makes a plastic-like material from milk and vinegar (an acid). Answer the parts to explain why this does not show that a new polymer was made.
What polymer does milk already contain?
(1)What does the vinegar do to the casein?
(1)What do filtering and drying do?
(1)So was a new polymer made? Why?
(1)Total for this question: 4 marks
Making plastics
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To make “milk plastic”, warm milk is mixed with vinegar. Lumps of casein (a protein) form. The lumps are filtered off and pressed into a shape.
What is the job of the vinegar?
(1)Kai wants to find out how the volume of vinegar affects the mass of plastic made. Give two variables he should control.
(2)Kai weighed each lump straight after filtering. Explain why this could give misleading results, and how he could improve the method.
(2)Total for this question: 5 marks
Should we switch?
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Illustrative data: a reusable bottle needs 100 energy units to make and 2 units to wash for each use. A disposable bottle needs 10 units for each use.
Calculate the total energy for the reusable bottle after 20 uses.
(1)Calculate the total energy for disposable bottles over 20 uses.
(1)How many energy units lower is the reusable bottle after 20 uses?
(1)Evaluate the choice of the reusable bottle using this model.
(2)Total for this question: 5 marks
Should we switch?
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A café is deciding whether to switch from plastic cups to paper cups. The table compares one cup of each type.
| plastic cup | paper cup | |
|---|---|---|
| energy to make / kJ | 420 | 550 |
| water used to make / litres | 0.5 | 1.8 |
| carbon dioxide released when made / g | 24 | 33 |
| time to break down as litter | about 450 years | about 3 months |
Which cup uses less energy to make?
(1)The manager says, “Paper cups are always better for the environment.” Use the data to give one point that supports the manager and one point that does not support the manager. Then give one further piece of information the manager would need before deciding.
(3)Total for this question: 4 marks
How does recycling work?
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Plastics are sorted and cleaned before they are recycled. Answer the parts to explain why.
What does sorting separate?
(1)What can happen if different plastics are melted together?
(1)What does cleaning remove?
(1)What would happen to the recycled plastic if it was not cleaned?
(1)Total for this question: 4 marks
How does recycling work?
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At a recycling plant, mixed waste moves along a belt. Different methods are used to separate the materials.
Steel is magnetic. An eddy-current separator pushes metals that are not magnetic off the belt. Polythene is less dense than water.
Choose the method used to separate each material.
(2)Two plastics, PET and PVC, are mixed together. Both sink in water. Explain why it is important to separate them before melting them down for recycling.
(2)Total for this question: 4 marks
Effects on wildlife
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Animals such as turtles and seabirds can get tangled in plastic. Answer the parts to explain how this can stop them surviving.
What does the plastic do to the animal?
(1)What can the animal not do properly?
(1)Give one thing the animal needs to move for.
(1)So what happens to its chance of survival?
(1)Total for this question: 4 marks
Effects on wildlife
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Scientists studied seabirds on an island. Each year they counted the pieces of plastic in the stomachs of birds that were found dead.
Describe the trend shown by the graph.
(1)Plastic is not poisonous. Explain how plastic in the stomach could still cause a bird to die.
(2)The scientists only studied birds that were already dead. Suggest why this might make their mean higher than the mean for the whole population.
(1)Total for this question: 4 marks
Natural polymers
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Name two natural polymers and state one correct function of each.
(4)Total for this question: 4 marks
Natural polymers
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Starch, cellulose, protein and DNA are natural polymers.
What is meant by a polymer?
(1)Choose the monomer that each polymer is made from.
(2)Give one way natural polymers are similar to plastics and one way they are different.
(2)Total for this question: 5 marks
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